The present invention is directed to an apparatus and method for the electromagnetic inspection of cannula alignment. More particularly, the present invention is directed to an apparatus and method for the electromagnetic inspection of cannula alignment in a cannula shield attached to a syringe.
Syringes are often supplied with a cannula (or needle) that is pre-attached to the syringe barrel and covered by a cannula shield during manufacturing. A common method of forming the outlet of a syringe barrel is to roll the barrel whilst it is in a heated and softened condition onto a mandrel to form a hole into which the cannula is bonded. For safety purposes, a cannula shield is placed over the cannula and firmly but removably attached to the syringe barrel. Desirably, the longitudinal axes of the syringe barrel, the cannula and the cannula shield should be coincident. However, during the manufacturing process, the cannula and/or the cannula shield may be angularly displaced from the longitudinal axis of the syringe barrel. In such instances, the cannula may pierce the cannula shield. Accordingly, the syringe must be inspected during the manufacturing process to assure that the cannula, cannula shield and syringe barrel are properly aligned.
To determine the angular displacement of the cannula within a cannula shield, some conventional electromagnetic inspection devices may have two radiation sources that are able to irradiate and penetrate the cannula shield from two different locations preferably spaced about the longitudinal axis approximately forty-five to ninety degrees apart. Other conventional electromagnetic inspection devices may have a mechanism that rotates the syringe to obtain images from two different perspectives. Such conventional inspection devices require the analysis of two images to determine the angular displacement of the cannula.
Accordingly, there is a need in the art for an apparatus and method for the electromagnetic inspection of cannula alignment based on the analysis of a single image as opposed to multiple images.